A conventional bandwidth control method for a communication system configured to include a plurality of slave station devices and a master station device that accommodates therein these slave station devices is a method of using a control such as that to dynamically distribute upstream bandwidths to the slave station devices that request bandwidth allocation in proportion to contract bandwidth ratios of subscribers that use the respective slave station devices.
For example, a communication system described in Patent Literature 1 mentioned below is configured to allocate bandwidths to slave station devices based on not only contract bandwidths of subscribers but also an accumulated value of bandwidths previously allocated to the slave station devices or that of data previously transmitted to the slave station devices so as to distribute upstream bandwidths to the slave station devices in proportion to the contract bandwidth ratios of the subscribers, respectively.